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    FORM 4 BIOLOGY PP1 REVISION EXAMS PLUS ANSWERS FREE

    Hillary KangwanaBy

    Name…………………………………………………          adm no. ……………class…….

    School …………………………………………………                    

    231/1

    BIOLOGY

    PAPER 1

    Time:  2 HOURS

    KASSU JET EXAMINATION 

    231/1

    BIOLOGY PAPER 1

    Time:  2  HOURS

    INSTRUCTIONS TO CANDIDATES

    • Answer ALL the questions.
    • Answers must be written in the spaces provided in the question paper.
    • Additional pages must not be inserted.
    • The paper consists of 14 printed pages.

    FOR EXAMINERS USE ONLY

    Question Maximum score Candidate’s score
    1-29 80

     

    		  

     

    This paper consists of 13 printed pages. Candidates should check the question paper to ascertain that all the pages are printed as indicated and no questions are missing

     
    • How does growth as a characteristic of living organisms differ in plants and animals ?

    (2marks)

    ………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………

    1. a)State the role of active transport in animal nutrition (1mark)

    ………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………

    1. b) Cyanide lowers the rate of active transport. Explain?(2marks) ………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………
    2. The figure below is a diagram of a vertical section of a mammalian tooth.
    A
    B
    D

    (i)  Name the part labelled A and B.                                            (2 marks)

    A                                                                                       ………………………………………………………………………………………………

    C                           ………………………………………………………………………………………………

    (ii) State two ways in which structure D is adapted to its functions.                  (2 marks)

    ………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………

    (iii)            List two ways of preventing gingivitis.                                             (2 marks)

    ………………………………………………………………………………………………………………………………………………………………………………………………

    1. The figure below shows % saturation of oxygen in blood in fish as water passes along the gill plate.
    Distance along the gill plates
    % saturation of oxygen
    Water
    Blood

     

    (a) (i) Name the type of blood flow shown in the gill plate.                         (1mark)

    ……………………………………………………………………………………………… (ii) Explain the advantage of the type of flow named in a (i) above                        (2marks)

    ………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………

    (b) Statetwo organs in humans which display the type of flow named in a (i) above                                                                                                                                 (2marks)

    ………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………

    (c) State two ways in which floating leaves of aquatic plants are adapted to gaseous exchange                                                                                                         (2marks)  ………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………

    1. The equationbelow shows an oxidation reaction of food substances.

    C51H98O6 + 145O2   ——- X CO2   + 98 H2O + energy

    1. a) What do you understand by the term respiratory quotient?  (1mark)

          ………………………………………………………………………………………………….……………………………………………………………

    1. b) Determine respiratory quotient of the oxidation of food substance.  (2marks)

     

     

     

    1. c) Identify the food substances.                                                              (1mark)

    …………………………………………………………………………………

    1. When any one of the growth parameters such as growth in size or weight, increase in number of cells are plotted in a graph against time like below, a clearcurve isobtained

    State its name………………………………………………………………………..   (1mark)

    1. The graph below represents the growth in a certain phylum.

     

     

     

    How does this differ from growth in humans?                                                 (1mark)

     

    ………………………………………………………………………………………………………………………………………………………………………………………………

    1. The embryo of a dry, fully developed seed usually passes through a period of rest after ripening period and it cannot germinate even when provided with all favorable conditions. State the significance of this. (2marks)

    ……………………………………………………………………………………………………………………………………………………………………………………………………………………………………

    1. a) Cowpeas seeds were place in a vacuum flask and left for five days. What is the expected change in composition of gases in the flask on the sixth day?                         (1mark)

     

    …………………………………………………………………………………………………

    1. b) Give a reason for your answer in (a) above (1mark)

    …………………………………………………………………………………………………

    1. Biotechnologist works day a night to curb food insecurity using the knowledge of polyploidy in genetics. Explain the economic importance of such practice?             (2marks)

    ………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………

    1. b) Define a backcross? (1 mark)

    ………………………………………………………………………………………………………………………………………………………………………………………………………………

     

    1. The structure belowwasobtainedfrom an animal cell
    2. Whatis the name of the hair like processes and state itsfunction? (2marks)

    Name

    …………………………………………………………………………………………..

    Function

    …………………………………………………………………………………………..

    1. Fromwhich parts of the mammalian body are these structures found? (1mark)

    …………………………………………………………………………………………..

    1. State the effect of cigarette smoking to the structure?                     (1mark)

    ……………………………………………………………………………………………………………………………………………………………………………………………….

    1. A student was found to have blood group B+
    2. a) What type of antibody is present in his plasma? (1mark)

    …………………………………………………………………………………

    1. b) Whichantigens are present in thisblood group? (1mark)

    ………………………………………………………………………………….

    1. Plants relatively have less waste to excrete than animals. Give two reasons to explain this observation (2marks) ………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………
    2. Statetwomethods by which plants get rid of their waste products (2marks)

    ………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………

    1. To estimate the population size of mosquitoes in Banji village thatcovers an area of 25km2, visiting researchers caught 400 mosquitoes which they marked and released.  After 24 hours, 200 mosquitoes were caught out of which 120 had not been marked.

    (a) Suggest the sampling method described above.                    (1 mark)

    ………………………………………………………………………………………………

    (b) What are the disadvantages of this method?                                     (2 marks)

    ……………………………………………………………………………..………………………………………………………………………………………………………………………..……………………………………………………………………………………………………………………………………………………..…………………………

     

    1. The table below shows stomatal distribution on leaves A and B and their surface area. Use the information to answer the questions.
      Leaf surface   A  B
    Number of

    stomata

     

     

     

    		 Upper leaf

    surface

    		        20    5
    Lower leaf

    surface

    		         0    15
    Surface area

     

    		   25 cm2  18cm2

    Identify with reasons the habitats of the plant from which the leaves were obtained.

    Leaf A:                                                                                                      (2 marks)

    Habitat            ……………………………………………..….…………..…………..

    Reason                  ……………………..………………….…..….….…..……………….

    ………………………………………..………………………………

    Leaf B:                                                                                                      (2 marks)

    Habitat            ………………………………………………………………………………

    Reason            ………………………………………………………………………………

    ……………………………………………………………………………

    1. Name the causative agent of the following diseases (2 marks)

    (i)  Trichomoniasis.

    ………………………………………………………………………………………………

    (ii) Gonorrhea

    ………………………………………………………………………………………………

     

     

    1. The diagram below shows a pollen tube as it develops down the style. Use it to answer the questions that follows;

    (i)  Name the part labelled G.                                                                  (1 mark)

    ………………………………………………………………………………………………

    (ii) State two functions of structure labelled E.                                      (2 marks)

    ………………………………………………………………………………………………………………………………………………………………………………………………

    1. (a) Define parthenogenesis?                                                                          (1 mark)

    ………………………………………………………………………………………………………………………………………………………………………………………………

    (b) Name the plant hormone that induces fruit ripening.                               (1 mark)        ………………………………………………………………………………………………

    1. A group of Form Three students collected a certain specimen for study as shown below.            Study it carefully and use it to answer the questions that follow.

    (i)  Name the type of metamorphosis in the above specimen.                                           (1 mark)

    ………………………………………………………………………………………………

     

     

    (ii) Give any two advantages of the above metamorphosis.                          (2 marks)

    ………………………………………………………………………………………………………………………………………………………………………………………………

    1. (i) Give two structural features in a leaf that adapts it to absorb Carbon (IV) Oxide.                                                                                                             (2 marks)

    ………………………………………………………………………………………………………………………………………………………………………………………………

    (ii) Name the cell organelle in which Carbon(IV)oxide combines with water to form a complex organic compound takes place                                            (1 mark)

    ………………………………………………………………………………………………

    1. In an experiment to investigate a factor affecting photosynthesis; leaf of a potted plant, which had been kept in the dark overnight was covered with an aluminum foil as shown in the diagram below.  The set up was kept in the sunlight for three hours after which a food test was carried out on the leaf.

    (a) Which factor was being investigated in the experiment?                 (1 mark)

    ………………………………………………………………………………………………

    (b) Which food test was carried out?                                                      (1 mark)

    ………………………………………………………………………………………………

     

     

    (c) State the results of the food test.                                                       (1 mark)

    ………………………………………………………………………………………………………………………………………………………………………………………………

    1. Explain how the following plant adaptations minimizes rate of transpiration (2marks)
    2. a) Sunken stomata

    ………………………………………………………………………………………………………………………………………………………………………………………………

    ………………………………………………………………………………………………

    1. b) Thick cuticle

    ………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………

    1. Explain how drooping of leaves on a hot sunny day is advantageous to a plant (2marks)

    ………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………

    1. Name two tissues in plants which are thickened with lignin (2marks)

    ………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………

    1. The diagram below shows the front view of a male reproductive system.
    2. Give the functions of the structures labelled X and V (2marks)

    X

    ………………………………………………………………………………………………………………………………………………………………………………………………

     

    V

    ………………………………………………………………………………………………………………………………………………………………………………………………

    1. What is the role of Follicle Stimulating Hormone in male reproduction? (1mark)

    ………………………………………………………………………………………………………………………………………………………………………………………………

    1. 27. Explain why the concentration of insecticides in fish eating birds may be hundreds oftimes greater than its concentration in the water where the fish live(3marks)

    ………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………

    1. The diagram below shows a stage in meiosis

    State the biological significance of the stage represented on the diagram above (1mark)

    ……………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………….

    1. Howdo the following factors hinder self-pollination in flowering plants? (3marks)
    2. a) Self-sterility

    ………………………………………………………………………………………………………………………………………………………………………………………………

    1. b) Heterostyly

    ……………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………..

    c)Protogyny

    ………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………

    MARKING SCHEMES.

    Name…………………………………………………          adm no. ……………class…….

    School …………………………………………………                    

    231/1

    BIOLOGY

    PAPER 1

    Time:  2 HOURS

    KASSU JET EXAMINATION  

    231/1

    BIOLOGY PAPER 1

    Time:  2  HOURS

    INSTRUCTIONS TO CANDIDATES

    • Answer ALL the questions.
    • Answers must be written in the spaces provided in the question paper.
    • Additional pages must not be inserted.
    • The paper consists of 14 printed pages.

     

    FOR EXAMINERS USE ONLY

    Question Maximum score Candidate’s score
    1-29 80

     

    		  

     

    This paper consists of 13 printed pages. Candidates should check the question paper to ascertain that all the pages are printed as indicated and no questions are missing

    1. How does growth as a characteristic of living organisms differ in plants and animals?

    (2marks

    In plants growthoccurs at meristematic tissues only ;while in animalsgrowthoccurs all over the body ;

    1. a) State the role of active transport in animal nutrition (1mark)

    Reabsorbtion of sugars and somesalts in the kidney

    Absorption of digestedfoodfrom the alimentary canal into the bloodstream.

    Excretion of wasteproductsfrom body cells.

    1. b) Cyanide lowers the rate of active transport. Explain?(2marks)

    cyanide is an enzyme inhibitor, it affects the rate of active transport

    1. The figure below is a diagram of a vertical section of a mammalian tooth.

    (i)        Name the part labelled A and B.                                            (2 marks)

    A  Enamel

    B Gum

    (ii)       State two ways in which structure D is adapted to its functions.                  (2 marks)

    – Containsbloodvesselswhich supplies foodnutrients and oxygen and removecarbon IV oxide and nitrogenouswasteproducts;

                      – Contains nerve endings for sensitivity;

    (iii)      List two ways of preventing gingivitis.                                             (2 marks)

    – Regular brushing of teeth;

    -Proper exercise of the teeth by eating tough fibrous food;

    -Eatingfoodsthat are rich in vitamin C

     

    1. The figure below shows % saturation of oxygen in blood in fish as water passes along the gill plate.

     

    (a) (i) Name the type of blood flow shown in the gill plate.                         (1mark)

    Counter current flow

    (ii) Explain the advantage of the type of flow named in a (i) above                        (2marks)

    Creates a steep diffusion gradient; that enhances the rate of gaseous exchange across the gill filaments/ increases rate of gaseous exchange; through diffusion (Rej increases rate of gaseous exchange/enhances gaseous exchange alone

    (b) Statetwo organs in humans which display the type of flow named in a (i) above                                                            Kidney;  Placenta; Ileum                                                                               (2marks)

    (c) State two ways in which floating leaves of aquatic plants are adapted to gaseous exchange                                                                                                         (2marks)

    – Stomata found only on upper epidermis to allow efficient gaseous exchange;

                – Presence of large air-spaces/aerechyma tissue to enable floating and storage of air;

                – Lack cuticle to enhance gaseous exchange;

    1. The equationbelow shows an oxidation reaction of food substances.

    C51H98O6 + 145O2   ——- X CO2   + 98 H2O + energy

    1. a) What do you understand by the term respiratory quotient?  (1mark)

          Volumetricrelationshipbetween Carbon (IV) oxide produced and oxygenconsumed

     

    1. b) Determine respiratory quotient of the oxidation of food substance.  (2marks)

    R.Q = CO2 produced

                                                 O2 used up

    R.Q = 102/145

                                     R.Q = 0.7

     

    1. c) Identify the food substances.                                                              (1mark)

    Fat/ Lipid

    1. Whenany one of the growth parameters such as growth in size or weight, increase in number of cells are plotted in a graph against time like below, a clearcurve isobtained

    State its namesigmoid curve(1mark)

    1. The graph below represents the growth in a certain phylum.

     

     

     

    How does this differ from growth in humans?                                                 (1mark)

     

     In humans it’s continuous from time of birth to maturity when it slightly tails off while for

    this phylum it’s discontinuous /in intervals with shedding of exoskeleton

     

    1. The embryo of a dry, fully developed seed usually passes through a period of rest after ripening period and it cannot germinate even when provided with all favorable conditions. State the significance of this. (2marks)

    Provides the seedswithenough time for dispersal sothatthey can germinate in suitableenvironment

    Enables seeds to survive during adverse seeds to survive during adverse environmental conditions

    The embryo has time to developuntilfavourable conditions are available

     

    1. a) Cowpeas seeds were place in a vacuum flask and left for five days. What is the expected change in composition of gases in the flask on the sixth day?                         (1mark)

    Decrease in oxygen and increase in carbon(1V)oxide

    1. b) Give a reason for your answer in (a) above (1mark)

    Germinating seeds respire using oxygen and release carbon(IV)oxide

    1. Biotechnologist works day a night to curb food insecurity using the knowledge of polyploidy in genetics. Explain the economic importance of such practice?             (2marks)

    Increases yields in plants

    Cause early maturity in plants

    Enhance resistance to pest, disease and drought

     

    1. b) Define a backcross? (1 mark)

    A cross between an offspring with one of its parents

    1. The structure belowwasobtainedfrom an animal cell
    2. Whatis the name of the hair like processes and state itsfunction? (2marks)

    Name

    Cilia

    Function

    Propel mucus or a fertilised ovum  

    1. Fromwhich parts of the mammalian body are these structures found? (1mark)

    Trachea and oviduct

     

    1. State the effect of cigarette smoking to the structure? (1mark)

    Cigarettes contain tar which impairs/inhibit the action of cilia in the respiratory tract leading to cancer.

    1. A student was found to have blood group B+
    2. a) What type of antibody is present in his plasma? (1mark)

    a

    1. b) Whichantigens are present in thisbloodgroup? (1mark)

    B and Rhesus antigens

    1. Plants relatively have less waste to excrete than animals. Give two reasons to explain this observation (2marks)

    Plants reuse some of their waste products;

    Plants produce their waste products slowly compared to animals that produce slowly ;

    1. Statetwomethods by which plants get rid of their waste products (2marks)

    Diffusion

    Transpiration

    Guttation

    Exudation

    Deposition   (anytwo)

    1. To estimate the population size of mosquitoes in Banji village thatcovers an area of 25km2, visiting researchers caught 400 mosquitoes which they marked and released.  After 24 hours, 200 mosquitoes were caught out of which 120 had not been marked.

    (a)       Suggest the sampling method described above.                    (1 mark)

    Capture recapture method

    (b)       What are the disadvantages of this method?                                     (2 marks)

    –Some organism may die during the study period;

    -The mark may come the out during the study period;owtt

    1. The table below shows stomatal distribution on leaves A and B and their surface area. Use the information to answer the questions.
      Leaf surface   A  B
    Number of

    stomata

     

     

     

    		 Upper leaf

    surface

    		        20    5
    Lower leaf

    surface

    		         0    15
    Surface area

     

    		   25 cm2  18cm2

    Identify with reasons the habitats of the plant from which the leaves were obtained.

    Leaf A:                Habitat          Fresh water;         (1 mark)

    Reason;        Maximum number of stomata on the upper leaf surface for quick loss of excess water by transpiration;(1 mark)

    Leaf B:                Habitat:         Savannah/ Rain forest;         (1 mark)

    Reason               :More stomata on loer surface than on the upper to reduce the surface area exposed to excessive loss of water by transpiration

    (1 mark)

    1. Name the causative agent of the following diseases (2 marks)

    (i)        Trichomoniasis.

    Trichomonasvaginalis

    (ii)       Gonorrhea

    Neisseriagonorrhoea

    1. The diagram below shows a pollen tube as it develops down the style. Use it to answer the questions that follows;

    (i)        Name the part labelled G.                                                                  (1 mark)

    Pollen tube;

    (ii)       State two functions of structure labelled E.                                      (2 marks)

    -Fuse with the egg cell nucleus to form zygote

    –Fuse with polar nuclei to form a triploidendosperm nucleus;

    1. (a) Define parthenogenesis?                                                                          (1 mark)

    A type of asexual reproduction in insects where eggs produced without being fertilized are able to hatch into adult insects;

    (b)       Name the plant hormone that induces fruit ripening.                                     (1 mark)Ethylene;

    1. A group of Form Three students collected a certain specimen for study as shown below.            Study it carefully and use it to answer the questions that follow.

    (i)        Name the type of metamorphosis in the above specimen.                                     (1 mark)

    Complete metarmophosis;

    (ii)       Give any two advantages of the above metamorphosis.                          (2 marks)

    Each stage occupies a different ecological niche; hence there’s no competition for resources e.g food;

    1. (i) Give two structural features in a leaf that adapts it to absorb Carbon (IV) Oxide.     Broad lamina;

                – Many stomata

    (ii)       Name the cell organelle in which Carbon(IV)oxide combines with water to form a complex organic compound takes place                                            (1 mark)

      Chloroplast

    1. In an experiment to investigate a factor affecting photosynthesis; leaf of a potted plant, which had been kept in the dark overnight was covered with an aluminum foil as shown in the diagram below.  The set up was kept in the sunlight for three hours after which a food test was carried out on the leaf.

    (a)       Which factor was being investigated in the experiment?                 (1 mark)

    Light;

    (b)       Which food test was carried out?                                                      (1 mark)

    Starch test;

    (c)       State the results of the food test.                                                       (1 mark)

    Starch absent/Iodine retains its brown colour/starch test negative;

    1. Explain how the following plant adaptations minimizes rate of transpiration (2marks)
    2. a) Sunken stomata

    Water vapour accumulates in the pits  reducing water vapour diffusion gradient hence reduced transpiration rate;

    1. b) Thick cuticle

    Reduces permeability of the leaf to water thus reducing water loss;

    1. Explain how drooping of leaves on a hot sunny day is advantageous to a plant (2marks)

    The leaves expose a smaller surface area to the sun thus reducing excessive water;

    1. Name two tissues in plants which are thickened with lignin (2marks)

    Parenchyma cells;

    Xylem vessels;

    1. The diagram below shows the front view of a male reproductive system.
    2. Give the functions of the structures labelled X and V (2marks)
    3. Provide an alkaline fluid which contains nutrients for the spermatozoa;
    4. Seminiferous tubules which provides a large surface area for production of sperms;
    5. What is the role of Follicle Stimulating Hormone in male reproduction? (1mark)

    Stimulates the synthesis and maturation of sperms;

    1. 27. Explain why the concentration of insecticides in fish eating birds may be hundreds oftimes greater than its concentration in the water where the fish live(3marks)

    Aquatic plants in water absorb the pesticides that drain into water bodies and soaccumulate ,fish consume smallquantitiesevery time the ingest the water thisalsoaccumulates in the fishwith time, as the birds continue feeding the contaminatedfishthey pesticides increase in levels

    1. The diagram below shows a stage in meiosis

    State the biological significance of the stage represented on the diagram above(1mark)

    The exchange of DNA hence increases genetic variation;

    1. Howdo the following factors hinder self-pollination in flowering plants? (3marks)
    2. a) Self-sterility

    It is a condition where pollen grains from the anthers cannot grow on the stigma of the same flower of plant/ are incompatible to stigma of the same plant/flower;

    1. b) Heterostyly

    Is a condition of having different arrangements of style and stigma i.e. shorter stamen than pistil;

    c)Protogyny

    it’s a condition where the female matures an its ready to receive the pollen grains before the male parts mature;

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